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Leonardo: The TWAINAquireExt function

This begins the actual scanning process by calling the software used by the device to initiate a scan or other type of data acquisition. The acquisition software's window will behave similarly to a nonmodal Windows dialog. The scan process depends on the correct use of the Function TWAINIsTwainMessage. in the applications message loop. Applications can avoid to implement changes to the message loop by using the Function TWAINGetImage.

This function provides a supplementary bShowUserInterface parameter allowing scanning a picture without user contact.

BOOL bShowUserInterface,
UINT uBitCount);
hta Handle to TWAIN memory created by TWAINInitialize
bShowUserInterface Specifies whether or not to allow access to the user interface for the TWAIN data source. If FALSE, then no user interface is displayed and the scanning process or data acquisition process begins immediately.
uBitCount If bUserInterface is FALSE, the Application defined the biBitCount value for the DIB to be created in this Parameter. Possible Values are:

TWAIN_COLOR_DEFAULT: The bitCount ist to be defined by the last user interface setting used.

TWAIN_COLOR_BW: The Image is Black & White only

TWAIN_COLOR_GRAY: The Image is in grayscale values 0..255

TWAIN_COLOR_RGB: The Image is in colors with 24 bits per pixel.

See also:

Þ problems with TWAIN - implementations

Þ example for unattended scanning

Þ function TWAINAquire

Þ function TWAINAquireExt

Þ function TWAINSetResolution

Þ function TWAINSetRect

Þ function TWAINCallDS

Þ function TWAINIsDSMOpen